Some commonly-grown garden or house plants can induce mild itching or, in some people, more serious allergic reactions. There are also a few plants that, if contact is combined with bright sunlight, may cause more severe problems
Images: Tim Sandall
Assessing the risk of contact with plants
There are a multitude of gardening tasks that involve touching plants; weeding, pruning, bulb planting and taking cuttings to name but a few. Undertaking these general garden tasks rarely causes adverse reactions but in order to minimise risks it is worth noting which plants
are most likely to cause irritation on contact
and how this can be brought about.
There are three main types of contact hazard. Some plants have sap that causes problems on contact; others contain chemicals that affect some people; and a few have irritant hairs.
Plants with irritant sap
Sap from some plants can affect anyone. When it gets onto exposed skin, it may cause a burning sensation and sometimes blistering. House plants such as Dieffenbachia, Schefflera, Epipremnum, Spathiphyllum (peace lily) and Monstera deliciosa (Swiss cheese plant) are common examples.
Allergen plants
The second group of plants contain chemicals called allergens. These do not affect everyone, but some individuals may acquire sensitivity to them, resulting in an allergic reaction. People who handle plants regularly such as florists can frequently become sensitised to specific plants. Alstroemeria and bulbs such as tulips, hyacinths and daffodils are common culprits.
More widespread sensitivity can develop with Euphorbia, which produce milky sap (below left), although sap from Euphorbia pulcherrima (poinsettia) is seldom harmful. Houseplants that can cause skin allergies include Ficus benjamina (weeping fig), Primula obconica (below right) and asparagus fern.
Phytotoxic sap
Some plants have sap that renders skin excessively sensitive to strong sunlight.
Contact with the plant followed by exposure to sunlight results in severe, localised sunburn with blistering and long-lasting skin discoloration.
Ruta (rue) and Heracleum (hogweed) are classic examples. If you come into contact with these plants when mulching or weeding, ensure skin is covered and avoid strimming near plants to prevent contact with face and eyes. Celery, parsnips and other plants from Apiaceae (hogweed family) may also cause skin blistering.
Hazardous hairs
Some plants have irritant hairs such as Fremontodendron and members of the borage family (such as Echium, Pulmonaria, Symphytum and Myosotis). These cause skin itching, and if breathed in can lead to respiratory problems. Such plants are best handled with gloves, and take care not to breathe in the hairs when exposure is intense, such as when pruning.
Helen Bostock